The objectives of the proposal are to: (a) Develop methods for isolation of membrane lipoproteins. (b) To purify individual lipoproteins and determine the mechanism of binding between the lipid and protein. (c) To determine if specificity exists for complex formation between specific lipids and proteins. (d) To establish the roles and degree of essentiality of lipids in the activity of membrane- bound enzymes. (e) To establish which lipoproteins are capable of membrane formation when complexed with lipids and to explore the mechanism of membrane formation in lipoprotein model systems.